ABSTRACT The goal of this patient-oriented study is to obtain health-related quality of life (HRQOL) outcomes data on patients who present with adult symptomatic lumbar scoliosis (ASLS) pre- and post-treatment in order to facilitate the development of evidence-based treatment guidelines, improve patient care and optimize healthcare resource utilization. We are defining ASLS as Oswestry Disability Index (ODI) e20, Scoliosis Research Society (SRS) domain scores d4.0 and a Cobb measurement of e30 at baseline. This study will help us determine how much the current treatment, either nonoperative or operative, improves the lives of people with this pathology. Significance: The impetus for this critical effort is the significant burden of disease posed by adult scoliosis, which affects 2.5-4% of the North American population. The most symptomatic group of primary presentation ASLS patients are those between the ages of 40 and 80 with lumbar deformities - our target population for this study. This disease constitutes a significant problem in light of our aging population and the high cost of surgical treatment (at least $80,000 in hospital costs alone). Studies to date, however, have typically been limited, small, single institution and retrospective. The extent to which treatment benefits patients with ASLS is not well established. Preliminary data: The Spinal Deformity Study Group/Adult Deformity Outcomes section (SDSG/ADO), which was formed 7 years ago, has developed a multi-center effort specifically to study adult scoliosis and has established an infrastructure for collecting consistent multicenter data. The SDSG has 1) validated a disease-specific outcomes tool (the SRS patient-reported outcomes instrument) for adult spinal deformity; 2) developed and validated disease-specific radiographic tools; 3) analyzed outcomes for certain interventions for comparison of treatments; and 4) collected preliminary data regarding the impact of treatments on patient outcomes. Methods: The study will comprise a multicenter, prospective, randomized controlled trial (RCT) (30%) and consecutive cohort study (70%) of patients receiving current standard-of-care treatments and will use uniform clinical and radiographic assessments that have been validated by our group for assessment of these patients. Both nonoperative and operative care will be stan- dardized within the 5 centers. Quality of life will be assessed by SRS-QOL, ODI, SF-12, numerical rating scale (NRS) back pain and leg pain scores. Functional measures will include a walking treadmill test to assess speed and endurance in patients at baseline and 2 years post-treatment. Primary Aims: Measure the impacts and compare the outcomes of nonoperative and operative treatments in ASLS patients. Innovation: No outcomes study exists in any current peer-reviewed literature to document the effect of both nonoperative and operative treatment on any aspect of primary presentation adult spinal deformity.